Mark and Devon Slee are proving dairy farmers can remain profitable while adopting techniques to care for the environment.

The South Canterbury couple, who have 2640 cows on 1014 hectares at Ealing, south of Ashburton, won the supreme award at the Canterbury Ballance Farm Environment Awards, announced last week.

Mark Slee said it was great to win the award, and he and Devon were keen to highlight the good environmental practices they had adopted.

"There is a lot of concern about the expansion of dairying, and we just wanted to be out there saying 'this is what we are doing with our property'.

"It's worthy of mention," Slee said.

The couple began managing the family farm in 1991, after Mark's parents converted the original 365ha sheep farm to dairy in 1987.

They have since grown the business after buying the farm, two neighbouring properties and a run-off dairy support block. They now employ 13 full-time, and two part-time, staff.

Looking out for the environment has been a focus for the pair, especially since they want to have a long-term sustainable operation.

Mark said taking care of the environment did not have to be to the detriment of profitability, and Melrose Dairy was proof of that.

Most of the farm is now irrigated, using eight centre pivots, with only 6ha irrigated using the less-efficient and original border dyke system.

They also monitor soil moisture to assess how much water is needed, and use GPS technology to monitor green water from the dairy shed and manage its placement on the farm.

The couple are able to be more efficient with water, fertiliser and electricity usage.

"If we can be more efficient, it will be more profitable for us as well."

Each of the Slees' cows produces 475 kilograms of milk solids annually, much higher than the Canterbury average of around 382kg of milk solids per cow.

While centre pivots are one of the most efficient ways of irrigating, they do not mix well with established shelter belts, so many have been cut down.

However, Slee said it was always their intention to put shelter back in, and they had now planted about 8km of native shelter belts, which were low enough for the pivots to pass over.

"Big trees and centre pivots don't mix," he said.

Some of the other environmental practices they have adopted include burying any dead cows in sawdust and composting - which stops bacteria from decomposition leaching into groundwater - rather than the more traditional method of burying them in the ground.

All the green water from the dairy shed is used as fertiliser and slowly put back onto the pasture using the centre pivots.

Mark said he was always keeping up to date with environmental developments in the industry and was keen to implement more strategies.

The award judges said the Slees demonstrated an ability to run a highly profitable dairy business while ensuring "excellent environmental management".